In general, an electric car (or an electric automobile) or an electric vehicle (EV) means a vehicle using an electric battery and an electric motor instead of oil fuel and an engine.
Electric cars driven by rotating a motor by electric power accumulated in a battery were not put to practical use due to the heavy weight of the battery, a long charging time, etc. However, as environmental problems caused by pollution are becoming serious, electric cars are being developed from the 1990's. Recently, the global electric car market has rapidly grown and research has been actively conducted thereon.
In order to safely manage and handle a high-voltage battery or a high-capacity battery for use in electric cars, hybrid vehicles, etc., safety measures such as a control method and a physical method thereof are needed.
Among safety devices, a power cutting-off system for an electric car is a manual service disconnector (MSD) which is a system capable of selectively cutting off battery power to be supplied to an electric car according to the physical method.
That is, the MSD is capable of physically cutting off high-voltage battery power and is called variously according to a manufacturer thereof, e.g., a safety plug, a service plug, a disconnect switch, etc.
The MSD is used to prevent safety accidents from occurring during the manufacture, assembly, repair, delivery, etc. of an electric car. The MSD should be manufactured, whereby a user can easily cut off battery power, water-tightness is secured, a plug is not completely removed to prevent penetration of foreign substances while battery power is cut off when a high-voltage battery is delivered or needs to be repaired or a service thereof is needed, and other user convenience is secured.
The MSD should also have a shielding function to prevent interference with electronic components. Earthing should be maintained regardless of an external force caused by various vibrations occurring during driving of an electric car so as to stably maintain shielding performance.
Furthermore, when a plug is separated, sparks may be generated due to high voltage and thus safety problems may occur. Thus, measures should be taken therefor and the plug should be prevented from being arbitrarily separated due to an external force such as vibration.
Accordingly, there is a growing need for a power cutting-off system for an electric car, which is capable of stably maintaining shielding performance even during vibration of a vehicle, safely cutting off high voltage/current power, and preventing an unintended power cut-off caused by an external force such as vibration.